Portable electric light.



C. F. BURGESS.

PORTABLE ELECTRIC LIGHT.

APPLICATION FILED JULY5,1912.

Patented J an. 6, 1914.

mnmnms mc Lum. msmammb c.

-a very thin filament.

can be used, but the ilament, whether of UNTED stra/TES PATENT oE-EICE.

CHARLES' F. BURGESS, .0F MADISON, VTISCONSIN.

v'PORTABLE `ELECTRIC: LIGHT.

Specication of Letters Patent. y

Patented Jan. 6, 1914.

Application ledIuly 5, 1912. Serial No. 707,746.

To all whom it may concern: y

Be it known that I, CHARLES F. BUneEss, a citizen of the United States,residing at Madison, in the county of Dane and State of Wisconsin, haveinvented new and useful Improvements in Portable Electric Lights, ofwhich the following is a specification. A

The present invention relates to battery lamps of a portable characte,more partungsten or of other material, is necessarily very sensitive tochange in voltage at the batteries and is subject to disintegration atexcess voltage.

The normal or steady running voltage vof a battery cell is in theneighborhood of 1.3

volts so that with a two cell battery the normal lamp, voltage is in theneighborhood` of 2.6 volts. However, these batter cells, when new, havea voltage consi erablyy higher than this, as for instance 1.6 volts-percell, thisv being due to battery phenomena which need not here bediscussed in detail. In order that the lamps may give a satisfactorylight when the batteries have dropped to their normal running voltage of2.6 volts, it is necessary to greatly overload the lamp filament duringthepearlylifeof the battery. The practical result is that the lamps .aregreatly damaged during their early life on the batteries and so cannotwork i at maximum efficiency during the normal life of the battery andoftenv do not ontlast more than one vset of batteries. The high cost oflamps makes their renewal amaterial factor in the use of portablebattery lamps. j

According to the present invention a ref sistance is disposed inconvenient relation to the otherparts of a battery lamp and is connectedin such a 'manner that it may be cutinto the circuit when the batteriesare new per cell. dangerous overload and materially increases andoperating at normal voltage and can be cut out of circuit, progressivelyif desired, as soon as the batteries drop down to their normal operatingvoltage'of about 1.3 volts This protects the filament from its effectivelife without, however, impairlng the lightgiving qual-ities of thedevice when the batteries are 'operating at their normal. output. l.

An embodiment of the present invention is shown in the accompanyingvdrawing in which- Figure 1 is an elevation of a hand lamp withresistance wound about the tubular cas- A ing. Fig. 2 is a sectionalelevation, somewhat enlarged, o1 the structure shown in Fig. 1. Fig. 3isa detail of the circuit clos-v ing device.

' The' structure shown in the drawings has a I cylindrical casing 1 ofliber, or other suitelf r able insulating material, provided at orte endwith'a threaded metal collar 2 over which may be screwed a threaded cap3 arranged to hold the lens 4 and the reiiecto 1 v- 5 against the end ofthe fiber tube 1. Th

incandescent lamp 6 is screwed into thecen ter of the metal reflector 5and has a pro- 4jecting contact 7 for completing the circuit to one ofthe battery terminals.. l

The battery is contained in a pasteboard tube 8 and comprises aplurality of cells 9 and 10 placed end to end in usual'manner with thecarbon electrodes of the lowermost cell making .electrical connectionwith .the

zinc container of the cell immediately above. A coiled spring 11 carriedby the threaded end cap 'of the lamp holds the batteries firmly againstthe lamp terminal 7. A metal collar 13 secured to tube 1 serves to holdthe end cap' 12 in position.

Electrical connections from the zinc electrode of the lowermost batterytov the'outer or tubular electrode of-lamp 6 includes the spring ll'andcapI 12 and also Va conductor- '14C` arranged 4within the fiber tube 1and leading from the base of the lamp to a contact device placedy at.the side of the lamp in. convenient position. for.l manipulation bythe'operator.

The contact device of the structurel here lshown as an illustrativeembodiment ofthe present invention comprisesfa .meta-l box 15. rivetedto-the fiber tubeJ1`fandcarrying a spring tongue 16 which can bemanipulated: by vmeans of a button 17 'projecting-above the box withineasy reachv ofthethum'b of 'Sie the hand whichholds the'lamp. The rear4or trailing'end 18 of this tongue slides along the under face of thebox but can slip upwardl into notches or openings 19and 20 w'hichact asstops to govern the 4forward movement of the tongue. i

. The resistance used. to absorb the excess voltage Iwhen the lamps arenew maybe arranged in the form of a winding 21 wound about the fibertube 1 i'n a suitable recess, one end of this wire being dead-ended andthe other end 'being connected to a metal contact plate 22 permanentlyconnected with the conductor, 23 which leads to thel upper end 4of thelamp and is there connected with the retlector'f and 'thus with theouter ter- 'Ininal of the lamp 6. rlhe resistance wire, composed of anysuitable metal or-alloy and of suitable cross section and length, isprei!- crably oxidized/or enameled to insulate yadjacent turns, and thisprotective covering is scraped awayorremoved along the line of movementof 'spring 16. A forward movement' of the button 17, such Ias may be4effected-easily by the thumb of the operator, will force', spring 16forwardy into contact with .the resistance winding, thereby completingthe circuitfto' the battery, but includ- .ing the resistance in the lamp'circuit and so cutting down'the voltage on the filament to a-safevalue. The engagement of the trailing end 18 of the spring in the slot19. serves to 'govern the forward motion of the spring and by its-retarding motion indicates to the operator that the spring is on .thefirst step of the resistance. A further forward motionof the contactspring will progressively l cutout' the resistance until, when thespring .is in directcontact with plate the resistance will-be all out ofcircuit and the 'lamp i willbe connected directly. across the batteryvOrdinarily, the filament to be used in the ,lamp will-be adjusted -tothe normal voltage of the battery with which it is to be used .and the'resistance 21 will be employed to cut down the excess voltage ot thebattery during that intervalof time which may 'elapse before 'thebatteries settle down to 'their-normal working voltage.

. While 1 have herein set forth with some `'degree 'of particularity vanembodiment of and advantages. 'l

this invention, it should be understood that the invention issusceptible of a variety of j other embodiments and many minor changesmaybe made in the parts herein set forth Without departure from thespirit of the invention and withoutsacrificing its benefits Having thusdescribed my invention, what I claim as new vand desire to secure byLet`- ters-Patent of the United States is: 1L In a hand lamp, thecombination of a casing, a plurality. of batteries arranged therein andconnected in series, a lamp in lcontact with the inner electrode of oneof said batteries, a resistance winding for thc 'lampcircuit encirclingsaid casing and permanentlyconnected to one terminal of" the lamp, and asliding circuit closer permanently connected with vone of' said(batteries 70` and movable intoyand out'of contact with said resistancewinding and over successive turns thereof to vary the battery voltageatsaid lamp.

9.. -In a pocket lamp, the combination of a 7.5

casing, a plurality of batteries within said casing, a lamp contactingwith the endot' one of said batteries, a resistance wire encircling saidcasing in a plurality of turns and'lying iusli with the exterior.thereof, 80

said wire being permanently connected with one .terminal4 of said lamp,and a sliding circuit closer pern'ianently connected with a batteryelectrode and movable by the thumb Aof the operator, across'said'resistance wire 85a and a sliding circuit closer' withinv reach of 95the operators thumb 1and movable along said casi'ng'into and out ofcontact with said resistance wire to complete and control the circuitthrough said Wire to said lamp.

4.-. In a hand lamp, the combination of a cylindrical casing, alampmounted at the end of said casing, batteries arranged in seriesA withinsaid casing, 'a resistance wire wound about said casing 'and embedded.

therein flush with the exterior, means pcr- 105 manently .connecting oneend of said wire with said lamp, the other end being free, aslidingcircuit closer within reach of the operators thumb when the casing isheld in the'hand, said circuit closerv being permalllO Anently connectedwith one of said batteries and movable to complete the circuit throughsaid wire to said lamp and adjustable along said wire tti-protect saidlamp from the'highinitial voltage oi' saidbatteriesand to com- 115pensate for changes in the batteries as they age, and .stops governingthe forward movement of the circuit closer. i

In witnesswhereoil hereunto subscribe' my name to this specification inthe presence of two Witnesses.

CHARLES F. BURGESS. lVitnesses:

NAOMI M. BAYLIS, Bassin M. Gleason.

a plurality of batteriesw90

